1. Field of the Invention
This invention relates to a high speed printing apparatus for high speed intermittent printing on labels fed from a continuous supply roll.
2. Description of the Prior Art
There exists, in the prior art, label printing apparatus for printing on labels, in which a supply of labels having uniform indicia applied thereto are transported past a printer which then prints selective, variable indicia on each of the labels. Use of such pre-printed labels requires precision control in feeding the labels to the printer. Since each label of the supply roll contains uniform pre-printed information, it is necessary to accurately feed a single label at a time so that printing of the individual indicia will take place on the same portion of every label. In most prior art systems in which labels are intermittently fed to a printer, a large start-up torque is placed on the motor for driving the label supply due to the large inertia of the supply roll. This large start-up torque is applied each time a label is to be printed, thereby requiring that a relatively large motor be used. In addition, such prior art apparatus often fail to accurately position the label for printing on the preselected area of the label. This is, in part, due to the large size of the motor required because of the high start-up torque.
There is therefore a need in the industry for a label printing apparatus which is capable not only of accurately positioning a pre-printed label at a printing station, but which is also capable of transporting a supply of labels into a printing position at high speed without placing a large start-up torque on the drive motor.